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J. H. BECKER AND w. s. BELLOWS. SPARK PLUG.

. APPLICATION FILED SEPT. 5, 1917. 1,315,202. PatentedSept. 9, 1919llllllll INVENT R S BY A ATTORNEY UNITED STATES PAT N OFFICE.

JOHN gr. BECKER, 0E PHILADELPHIA, PENNSYLVANIA, AND WARREN sJEELL'ows,or.

Y I WORCESTER, MASSACHUSETTS. I

SPARK-PLUG.

Specification of Letters Patent.

Application filed September 5, 1917. Serial No. 189,734.

To all whom it may concern:

' Be it known that We, JOHN H. BECKER, a citizen of the United States,residing in the city of Philadelphia, county of Philadelphia, and Stateof Pennsylvania, and WARREN S. BELLows, a citizen of the United States,residing in the city of Worcester, county of \Vorcester, and State ofMassachusetts, have invented certain new and useful Improvements inSpark-Plugs, of Which the following is a specification.

Our present invention comprehends certain improvements in spark plugswhich; tend toward greater serviceability and-in.- creasinge'liic'iency.

The mostextensively used type of spark plug is provided with a porcelaincore. Porcelain possesses high insulating properties as it gives uniformdistribution to elec '.trical strains and is peculiarly "capable ofwithstanding extreme temperature changes from an extreme cold conditionto an intensely hot one generated at the firing points of the plug uponthe ignition of an explosive charge. Furthermore, porcelain is not,under firing temperatures, susceptible to expansive or contractivechanges. Hence, it almost universally used as an insulator for thecentral electrode of spark plugs.

An inherent objectionable characteristic of porcelain resides in thefact that it is brittle and most spark plug troubles are directlytraceable to broken cores which produccgas leakage and short circuitsunder ordinary conditions of temperature and electrical tension.Furthermore, the breakage of porcelain cores of conventional plugsfrequently happens as a result of externally applied blows or strains,accidentally directed against the extended exposed portion thereof, suchas might happen upon the slippageof a \vrench or a pair of pliers whileapplying the plug-to the engine or the ignition cable to the plug. It isthe purpose of our invention to minimize this liability of breakage andstill retain the desirable and proven etficient characteristics ofporcelain as an insulator at the effective igniting points of the plug.

To the accomplishment of this, we provide a composite or sectional coremade of porcelain and fiber or other suitable non-brittle material. \Vehave found in practice that a core of this nature when provided with asuitable gasket between the sections renders a plug durable, gas-tightand efiicient for the purpose for which it is intended.

In the accompanying drawings, we have illustrated by way of examplecertain preferable embodiments of .our invention, in 'which Figure 1 isa view in side elevation partly in section of a conventional spark plugembodying the features of our invention.

Fig. 2 iS'a sectional 'view .of the composite core illustratedinconnection with Fig.1.

Fig. 3 is a- View in side elevation of a different form of plug equippedwith our improved compositecore. i

Fig. 4 is a cross sectional view of the 'same plug illustrating thearrangement and relative positioning of the parts.

Referring to Figs. 1 and 2 in detail, the composite core comprisessections 1 and 2. The lower section of the core is preferably made ofporcelain and has fixedly mounted or embedded therein a centralelectrode 3, thelower extremity of which projects there from,terminating in proximity to the grounded terminal l carried by thethreaded nut or bushing 5. The upper extending and exposed section ofthe core is preferably made of fiber or other non-brittle material andis provided with a bore 6 for the .accommodation of the upper extremityof'the central electrode 3. This boreis of sufficient "diameter toprovide a comfortable sliding fit so that the plug may be readilyassembled or disassembled should the occasionH-equire. The lowerextremity of the section is shouldered as at 7, so that a nut or ascrew-threaded sleeve 8 is capable of eingagi'ng therewith to keep it inplace t1 ough. the screw-threaded engagement with the nut 5 at- 9.

Interposed between the sections 1 and 2 is provided an asbestos or othergasket 10, which will serve to make gas-tight the joint thus preventingthe escape of compression or gas through the bore 6 or past the bushingor sleeve 8.

This gasket also serves as a cushion to 'relieve pressure from theorcelainsection, and prevents its breaking under pressure of the sleeve8. Furthermore, it prevents undue heating of the adjacent lowerextremity of the fiber section of the core.

Mounted upon the upper extremity of the core is a metal ferrule or cap11 and theretioned at the apertures connected therewith.

Refernng to Figs. 3 and 4-, the upper secthe core is provided with aseries ofv tion'of radially arranged apertures 13 and the centralelectrode is of two-part construction providing auxiliary sparkingpoints It posiso that the spark intensity may be observed by means ofwhich the firing efficieney of the plug may be regulated through theproper adjustment of these I auxiliary points as the upper section ofthe central electrode is adjustably mounted as shown. In thisconstruction, the upper fiber section 1 of the plug is held against thegasket 10 by swedgin over the metal of the bushing 5 as at 15 in closecontact with the shoulder 7 of the core.

hile we have erable embodiments of the principles of our invention, wedo this in an illustrative rather than in a definitive sense, desiringit to be understood that we wish to cover said principles in Whateverform they may be emied. Having thus described our invention, what weclaim as new herein and desire to secure by Letters Patent is: I

1. A composite core for spark plugs,

, extending through the porcelain eluding a porcelain end portion, anelectrode extending through the porcelain end portion and rigidtherewith, and a fiber shank portion loosely slidable on the electrodeand normally held rigidly with the porcelain end portion.

A composite core for eluding a porcelain end portion, an electrodeextending through the porcelain end portion and rigidly embeddedtherein, a fiber shank portion loosely slida-ble on the electrode, theadj acentends of the porcelain and fiber portions being cut ofii square,a packing washer between the said square ends, and means for clampingthe porcelain and fiber portions rigidly together.

3. A composite core for spark plugs, including a porcelainwend portion,an electrode end portion and rigidly embedded therein, a fiber shankportion loosely slidable on the electrode, means for clamping theporcelain and fiber portions rigidly together, and a second electrodemember. fitted adjustably in the fiber shank portion and terminating in=a spaced relation to the end of the first mentioned electrode toprovide an auxiliary spark gap, ,the fiber shank portion beingtransversely apertured at the point of the auxiliary spark gap.

spark plugs, in-

JOHN H. BECKER. vVl-KRREN S. BELLOl VS.

